1. Technical Field
The present invention relates to a manufacturing system, a manufacturing method, a management apparatus, a management method, and a computer readable medium. More particularly, the present invention relates to a manufacturing system, a manufacturing method, a management apparatus, a management method, and a computer readable medium used for manufacturing electronic devices with appropriate management of the manufacturing line.
2. Related Art
In recent years, the physical sizes of semiconductor elements have been significantly reduced. The size reduction of the semiconductor elements accordingly reduces the defect size which affects the characteristics of the semiconductor elements. Such size reduction in the semiconductor elements and defects increases the unevenness of the characteristics of the semiconductor elements. This poses a problem for the circuit manufacturing process. For example, the unevenness of the characteristics (such as the threshold voltages and current-voltage characteristics) of MOS transistors considerably influences the reliability of the entire circuits and the yield of the circuit manufacturing process.
In addition to the statistically detected unevenness mentioned above, local defects such as bit defects and spot defects are found in a few units out of 10,000 to 1,000,000 units. Such local defects also determine the reliability and yield of the circuits, and thus pose a problem for the circuit manufacturing process.
Referring to the electronic device manufacturing process, it has been attempted to reduce the above-stated characteristics unevenness and local defects of the elements so as to realize high reliability and yield. To achieve this goal, it is desired to promptly identify one or more manufacturing stages, among a plurality of manufacturing stages designed for manufacturing the electronic devices, in which problems are occurring and to appropriately change the processing conditions related to the manufacturing apparatuses performing the processes corresponding to the identified manufacturing stages with the problems.
Exemplary conventional methods to judge the acceptability of each manufacturing stage are described in the following. A test wafer or the like is thrown into the manufacturing line. Then, the thickness of the insulation film formed on the wafer is measured with the use of a scanning electron microscope (SEM). Alternatively, whether particle or metal contamination is present is examined in an optical manner or by using the X-ray. For example, Patent Document 1 discloses a technique to correct the operating conditions of an exposure apparatus with reference to processed state information obtained by measuring, for example, the shape of the pattern on a pilot wafer which is exposed to light using the exposure apparatus (please see the paragraphs [0034] to [0039] of Patent Document 1 and the like)
Referring to the manufacturing line of the electronic devices, which are manufactured under the policy of mass-production with a small number of varieties, such as memory devices, the quality of the manufacturing line is managed by monitoring the yield of the final products.
Patent Document 1: Japanese Patent No. 3371899
When the acceptability of the manufacturing line is judged by observing the pattern formed on the wafer, time limitations make it impossible to observe a large number of patterns. Therefore, it is difficult to determine the characteristics unevenness and local defects of the elements. Hence, it is possible to directly reflect the result of the observation, for example, to feed back the observed shape of the pattern to the exposure apparatus, but it has been difficult to obtain sufficient data for appropriately identify the problematic manufacturing stages or for finely adjusting the parameters set for the manufacturing apparatuses.
When the yield of the final products is monitored, a long time period is required to realize the feedback. In addition, it is difficult to sufficiently obtain the characteristics of the electronic devices which are completed as products. Therefore, it has been difficult to appropriately identify the problematic manufacturing stages and adjust the parameters set for the manufacturing apparatuses.